I hate to dissent, it's good overall, but the grey on the planet is a little flat. In the movie, Unicron had raised areas on the planet sphere that were a different shade of silver than the rest, and if you look on the original clamshell wings on Armada Unicron, he has them too. They're the parts that are silver rather than transparent.

Doing them in a different shade, or even a more silvery paint would really bring that detail back out. Of course, I'm not a kitbasher, so this is just my humble opinion.